This invention relates to bonding metallic elements with a laser beam.
It is known to bond two metal elements together by using an energy source, i.e., a laser beam, focused onto the surface of one of the elements and creating a molten pool of metal and as more laser energy is coupled into this pool, conduction causes the pool to enlarge until it contacts the other element to bond the two elements together. A problem occurring in making these bonds is the formation of cracks in the pool of metal as it cools and solidifies. Cracks serve as sites of localized corrosion and may propogate causing the bond or weld to fail. Cracking occurs with metals that are prone to crack if the pool is constrained throughout its periphery by the metallic element in which the pool is first formed. Peripheral stresses cause the pool to tear along liquid boundaries when it is in the two-phase state.